A typical system to ignite an oven burner of a gas stove comprises mainly to partially turn on a gas valve to leave gas through a pilot burner and to ignite the pilot burner manually with a lighted match or by means of a manual electric igniter. Once the pilot burner is ignited, the gas valve is completely open in order to ignite the burner of the oven.
However, one of the main problems of the typical system is that, sometimes, the oven burner does not ignite, whether the pilot burner is turned off at the moment that the oven burner is ignited or by air flows. In this way, a dangerous concentration of gas within the oven is provoked, and the user immediately need to turned off the gas valve. If the user wanted to turn the burner on again, he or she would had have to ventilate the area to prevent from a possible ignition of gas, that would cause an explosion.
At the present, there are some ignition systems for the ignition of gas burners, which already use electronic ignition systems. For example, The U.S. Pat. No. 3,914,092 assigned to Johnson Service Controls, it is referred to a direct spark ignition system for generating ignition sparks for igniting fuel discharged by a fuel outlet.
Another system for controlling a pilot burner and main burner gas valves of a gas furnace is shown in the U.S. Pat. No. 3,986,813 assigned to Cam-Stat Incorporated, including a pilot spark igniter and a pilot flame sensor. The system includes a relay having a first standby mode providing power to a spark ignitor circuit so that, when the thermostat switch is closed, a pilot valve solenoid is energized, and in a second operating mode disconnecting power from the power from the spark ignitor circuit and providing power to the main valve solenoid when the flame is sensed at the pilot burner. The system is provided with a fast responding circuit for operating the relay utilizing a 24 volts supply, with a 48 volts supply provided only for the flame sensor.
Other arrangements of gas burners that already use electronic ignition systems to operate are described and claimed in the U.S. Pat. Nos. 4,055,164; 4,082,493; 4,111,639; and 4,194,875, all of them related with control systems for the automatic ignition of the burners. However, in all the cases, these are referred for controlling the pilot and the main burner gas valves (U.S. Pat. Nos. 4,082,493 and 4,194,875); for controlling the ignition of an auxiliary fire nozzle and a main fire nozzle in a water heater (U.S. Pat. No. 4,055,164); or to a self-checking fuel ignition system, which effects periodic testing of the operability of the spark generating circuit (U.S. Pat. No. 4,111,639).
Finally, the applicant of the present invention, in its Mexican Patent application SN 964738 makes reference to an electronic ignition system for a gas stove. The system is shown in combination with a plurality of burners, which are located on the upper part of the stove and inside the oven of said stove. A plurality of electrodes are placed near and in coincidence with each burner, each electrode being activated to provide ignition sparks for the ignition of each burner. A spark generating circuit is connected with all the electrodes in order to generate the enough ignition sparks for igniting each burner. A plurality of switching means, which are connected to spark generating circuit, the switching means being independently connected by each one of a series of valves on the stove. So, each time that a valve is open, the spark generating circuit is activated in order to provide ignition sparks by each electrode of each burner. And a power source connected to the spark generating circuit. The improvement in this system being characterized by, a flame sensor circuit connected between the spark generating circuit and at least one electrode, which in a first operating period and once the spark generating circuit has been activated for igniting one or more burners, it is operable to detect the absence of flame on the burners producing a sound by means of a buzzer, and in a second period, it is operated for detecting the presence of flame in the burner, and emitting a visual signal, once the burners have been ignited.
As can be seen of the above, the application of electronic circuits for the ignition of gas burners has been advancing in different areas. So, the present application is referred to the application of an electronic ignition system for burners of gas stoves, which is an improvement to the Mexican patent application 964738 (U.S. patent application Ser. No. 141976).
The electronic ignition system is show in combination with a plurality of burners, which are located on the upper part of the stove and a burner inside the oven. A plurality of electrodes are placed near and in coincidence with each burner, each electrode being activated to provide ignition sparks for the ignition of each burner. A spark generating circuit is connected with all the electrodes in order to generate the enough ignition sparks for igniting each burner. A plurality of switching means, which are connected to spark generating circuit, the switching means being independently connected by each one of a series of valves on the stove. So, each time that a valve is open, the spark generating circuit is activated in order to provide ignition sparks by each electrode of each burner. And a power source connected to the spark generating circuit. The improvements being characterized by a reestablish circuit connected to the power source; a circuit for controlling a security valve, the security valve being closed after that various attempt for re-igniting the burner has been made and absence of flame is being detected on the burner; and a microprocessor connected to a circuit for the protection of low voltage, to a flame rectifying circuit and to the circuit for controlling a security valve, said microprocessor being programmed to generate first activation signals for the ignition of the burner, for monitoring the presence of flame on the burner and for emitting first sound signals to indicate that the burner has been ignited and, if no presence of flame is detected on the burner, for generating second activation signals in order to try again of ignite the burner until a maximum predetermined time period for the ignition of the burner has been exceed, said microprocessor generating alarm signals once the time for the ignition of the burner has been finished and for closing the flow of gas toward the burner.